Helicity Conservation and the Drell-Hiida-Deck Effect

Coexistence of the Drell-Hiida-Deck effect and true A1 resonance production fairly explains the complicated experimental situation that angular distributions of the normal to the decay plane appear as if the t-channel helicity were conserved but those of the p meson coming from the decay seem not to conserve the t-channel helicity. It is shown that the true A1 resonance conserves the t-channel helicity and its decay into the (JTC state occurs through the d wave dominantly. The angular distributions by the Drell-Hiida-Deck effect are studied also for the rr+rr-p state diffractively produced. Conclusions similar to those for the A1 mass region hold for the low mass rr+rr-p system.